function onBtnClick()
{
	var input = document.getElementById('first_name');
	input.value = 'New value';
}

function onInputFocus()
{
	var input = document.getElementById('first_name');
	input.value = '';
}

function onInputBlur()
{
	var input = document.getElementById('first_name');
	if(input.value == '') 
	{
		input.value = 'Initial Value';
	}
}

hhhhhhh